The long-term goal of these studies is to describe and isolate the surface antigens of human gliomas and to use these antigens and antisera raised against them as diagnostic, prognostic and therapeutic reagents. In the current year our goal has been to define, with immunochemical procedures, determinants suggested by our previous studies of cell-mediated cytotoxicity against human gliomas. Using immune precipitation techniques glioma-specific glycoproteins with approximate molecular weight of 23,000, 46,000 and 110,000 daltons have been described. Current studies involve the isolation and purification of these glycoproteins, as well as investigations on their functional role in the immune response to the tumor and in the regulation of tumor cell growth.